PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

In the design selection of pumping machineries for Intermediate pumping station,
the following conditions are to be taken into consideration.
The datas given above with reference to RL are indicative and are not to be
considered as final. After finalisation of tender, if any change in the site, RL s,
resulting in change of operating head of the pumps, the contractor should arrange
design & selection of pumping plant/machineries for approval by the department
before proceeding for order of the same. The contractor are required to visit the site,
conduct survey, collect necessary datas required in designing and selection of
suitable pumping plant/machineries. The detail design calculation including
selection of type of pumps, motor, motor control center including type of starters,
cabling and valves inside the pump house viz. Sluice/butterfly valves and Nonreturn
valves are to be furnished along with the tender.
Though the wall thickness of the pipes for rising main may be sufficient to
withstand very severe surge pressure, the valves in the pump house including the
delivery manifold is required to be properly selected so as to prevent the damage of
the machineries in the event of sudden tripping of pumps as a result of power
failure. In the case of intermediate pumping station, the picture is comparatively
worsen as the total head is comparatively higher. In such a situation, water
hammering would be quite severe in the event of power failure. Considering the
total pump head, the valves inside the pump house including the delivery manifold
should have a working pressure of not less than 1.5 times the working pressure. Non
return valves on the individual pump delivery lines are proposed to be provided
with dash pot arrangement to dampen the rate of closure towards the end of closure.
Air valves are to be provided in the rising main.
Technical specification of the horizontal split casing pump.
Codes and Standards : Has been detailed elsewhere in this document.
Design and Performance Requirement : Has been detailed elsewhere in this
document.
Drawing, data, curves and manuals : Has been detailed elsewhere in this
document.
Materials of construction : Has been detailed elsewhere in this document.
Inspection and Testing : Has been detailed elsewhere in this document.
Packing for Transportation : Has been detailed elsewhere in this document.
DTS : Detailed Tender Specification. Page 227